题解 | 分数线划定

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    static class Candidate{
        int id;
        int score;
        Candidate(int id, int score){
            this.id = id;
            this.score = score;
        }
    }
    public static void main(String[] args) throws IOException{
        BufferedReader bufReader = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer strTok = new StringTokenizer(bufReader.readLine());
        int n = Integer.parseInt(strTok.nextToken());
        int m = Integer.parseInt(strTok.nextToken());
        List<Candidate> list = new ArrayList<>(n);
        for (int i=0;i<n;i++){
            strTok = new StringTokenizer(bufReader.readLine());
            Candidate candidate = new Candidate(Integer.parseInt(strTok.nextToken()),Integer.parseInt(strTok.nextToken()));
            list.add(candidate);
        }
        list.sort((c1,c2) -> {
            if(c1.score != c2.score){
                return Integer.compare(c2.score,c1.score);
            }
            return Integer.compare(c1.id, c2.id);
        });
        int rank = (m*3)/2;
        int num=0;
        for(Candidate c : list){
            if(c.score>=list.get(rank-1).score){
                num++;
            } else{
                break;
            }
        }
        StringBuilder sb = new StringBuilder();
        sb.append(list.get(rank-1).score).append(" ").append(num).append(System.lineSeparator());
        for(int i=0;i<num;i++){
            sb.append(list.get(i).id).append(" ").append(list.get(i).score).append(System.lineSeparator());
        }
        System.out.print(sb.toString());
    }
}